Biometal Model A gets its name from Master Albert, who created it as his personal back-up system. It is unknown what happened to Model A after his creation, Albert presumably hiding him somewhere. Model A had no memories of his origin. Years later, Model A was found by Raiders in ancient ruins, but they lost it during an aerial Maverick attack led by Prometheus. Some Hunters that took the task to retrieve the Biometal managed to take Model A and start to transport it to Legion with a train, but they are also attacked by Mavericks. During the attack, Ashe/Grey are attacked by Prometheus and Pandora and megamerge with Model A, becoming the Model A Mega Man. By defeating powerful enemies, Model A absorbs the DNA Core into its database, allowing the user to access the new form and its powers, albeit at a somewhat limited scale.

After taking care of the Mavericks in the train, Model A decides to stay with Ashe/Grey, although he initially disapproves the ally's heroic attitude and prefers to avoid combat. When Model A defeats a Mega Man, a cypher within him is unlocked. When Vent/Aile is defeated, the last cypher is unlocked and Model A discovers his origin and guesses the origin of Ashe/Grey, but decides to not reveal it yet. The truth is eventually revealed by Master Albert inside Ouroboros, and now that his plan was in motion, he says that Model A is no longer necessary and will be destroyed alongside Ashe/Grey, who are only able to megamerge with Model A due to having his DNA. After a fierce battle, Ashe/Grey manage to defeat Albert, but Ashe/Grey collapses and is rescued by Vent/Aile. After the battle, Model A decides to stay with Ashe/Grey.